title: Macroamphiphilic components of thermophilic actinomycetes: identification of lipoteichoic acid in Thermobifida fusca.
abstract: The cell envelopes of gram-positive bacteria contain structurally diverse membrane-anchored macroamphiphiles (lipoteichoic acids and lipoglycans) whose functions are poorly understood. Since regulation of membrane composition is an important feature of adaptation to life at higher temperatures, we have examined the nature of the macroamphiphiles present in the thermophilic actinomycetes Thermobifida fusca and Rubrobacter xylanophilus. Following hot-phenol-water extraction and purification by hydrophobic interaction chromatography, Western blotting with a monoclonal antibody against lipoteichoic acid strongly suggested the presence of a polyglycerophosphate lipoteichoic acid in T. fusca. This structure was confirmed by chemical and nuclear magnetic resonance analyses, which confirmed that the lipoteichoic acid is substituted with beta-glucosyl residues, in common with the teichoic acid of this organism. In contrast, several extraction methods failed to recover significant macroamphiphilic carbohydrate- or phosphate-containing material from R. xylanophilus, suggesting that this actinomycete most likely lacks a membrane-anchored macroamphiphile. The finding of a polyglycerophosphate lipoteichoic acid in T. fusca suggests that lipoteichoic acids may be more widely present in the cell envelopes of actinomycetes than was previously assumed. However, the apparent absence of macroamphiphiles in the cell envelope of R. xylanophilus is highly unusual and suggests that macroamphiphiles may not always be essential for cell envelope homeostasis in gram-positive bacteria.
authors.affiliation: School of Applied Sciences, Northumbria University, Newcastle upon Tyne, NE1 8ST, United Kingdom.
authors.forename: Obaidur
authors.initials: O
authors.lastname: Rahman
authors.forename: Markus
authors.initials: M
authors.lastname: Pfitzenmaier
authors.forename: Oxana
authors.initials: O
authors.lastname: Pester
authors.forename: Siegfried
authors.initials: S
authors.lastname: Morath
authors.forename: Stephen P
authors.initials: SP
authors.lastname: Cummings
authors.forename: Thomas
authors.initials: T
authors.lastname: Hartung
authors.forename: Iain C
authors.initials: IC
authors.lastname: Sutcliffe
mesh_terms: D039903:Actinobacteria / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D002473:Cell Wall / Q000378:metabolism; D002849:Chromatography, Gas; D002852:Chromatography, Ion Exchange; D005227:Fatty Acids / Q000302:isolation & purification / Q000378:metabolism; D005784:Gene Amplification; D006094:Gram-Positive Bacteria / Q000235:genetics / Q000378:metabolism; D008070:Lipopolysaccharides / Q000302:isolation & purification / Q000378:metabolism*; D010802:Phylogeny; D012329:RNA, Bacterial / Q000235:genetics / Q000302:isolation & purification; D012336:RNA, Ribosomal, 16S / Q000235:genetics / Q000302:isolation & purification; D013292:Streptococcus agalactiae / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D013306:Streptomycetaceae / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D013682:Teichoic Acids / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D005227:Fatty Acids; D008070:Lipopolysaccharides; D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S; D013682:Teichoic Acids; C009900:lipoteichoic acid